Magnetic fields of low-mass pre-main-sequence stars and Brown Dwarfs

低质量前主序星和棕矮星的磁场

• 批准号: 105369318
• 负责人: Professor Dr. Ralph Neuhäuser
• 金额: --
• 依托单位: Institut für Astrophysik und Geophysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/105369318?language=en
• 关键词: Magnetic; fields; low; mass; pre

We propose to study magnetic fields in fully convective objects, both weak-line T Tauri stars and (young) Brown Dwarfs. In particular, we will observe the transition from the (/(-dynamo to another turbulent type of dynamo in M-type T Tauri stars (part 1) and in late-M and early-L type Brown Dwarfs (part 2), where we aim to directly measure magnetic fields for the first time. On the main-sequence, the transition from partly radiative to fully convective stars appears at spectral types around M4, but no break in activity nor the mean magnetic field was found here. On the contrary, the fraction of active stars is rising towards cooler stars before it eventually diminishes close to the boundary to Brown Dwarfs. Our strategy is to search for a transition between different types of dynamos by investigating fully convective objects and compare them to the well studied hotter partial radiative stars.In the first part of this project, we measure magnetic fields in young low-mass pre-MS stars by studying Zeeman broadening in magnetically sensitive atomic and molecular lines using established methods. In the second part, the quest for magnetic fields in Brown Dwarfs, we have to develop new strategies to detect Zeeman splitting. We will use high-resolution spectrographs like UVES and CRIRES at the VLT.

我们建议研究磁场完全对流的物体，无论是弱线金牛座T星和（年轻）棕矮星。特别是，我们将在M型金牛座T星（第1部分）和晚M型和早L型褐矮星（第2部分）中观察到从（/（-发电机到另一种湍流型发电机的转变，我们的目标是首次直接测量磁场。在主序星上，从部分辐射星到完全对流星的转变出现在M4附近的光谱类型，但没有发现活动中断或平均磁场。相反，活跃恒星的比例在接近棕矮星边界时最终减少之前，正在向较冷的恒星上升。我们的策略是通过研究完全对流的物体来寻找不同类型的发电机之间的过渡，并将它们与研究得很好的较热的部分辐射恒星进行比较。在这个项目的第一部分中，我们通过研究Zeeman加宽的磁性敏感的原子和分子线，使用现有的方法来测量年轻的低质量前MS恒星的磁场。在第二部分中，对棕矮星磁场的探索，我们必须发展新的策略来探测塞曼分裂。我们将在VLT使用UVES和CRIRES等高分辨率光谱仪。

项目成果

A POSSIBLE DETECTION OF OCCULTATION BY A PROTO-PLANETARY CLUMP IN GM Cephei

• DOI: 10.1088/0004-637x/751/2/118
• 发表时间: 2012-03
• 期刊: The Astrophysical Journal
• 作者: Wen-Ping Chen;S. C. Hu;R. Errmann;C. Adam;S. Baar;A. Berndt;L. Bukowiecki;Dinko Dimitrov;T. Eisenbeiss;S. Fiedler;C. Ginski;C. Gräfe;C. Gräfe;J. Guo;M. Hohle;H. Y. Hsiao;R. Janulis;M. Kitze;H. C. Lin;C. S. Lin;G. Maciejewski;G. Maciejewski;C. Marka;L. Marschall;M. Moualla;M. Mugrauer;R. Neuhäuser;T. Pribulla;T. Pribulla;S. Raetz;T. Röll;E. Schmidt;J. Schmidt;T. Schmidt;M. Seeliger;L. Trepl;C. Briceño;R. Chini;Eric L. N. Jensen;E. H. Nikogossian;A. K. Pandey;J. Sperauskas;Hiromitsu Takahashi;F. M. Walter;Zhenyu Wu;Xin Zhou